Improvement in scroll-sawing machines



- 2 Sheets-S heet1. W. C. MARGEDANT. SCROLL SAWING-MACHINE. 17o,'573, IPatented Nov. 30, 1875.

WITNESSES u PEIERS. PHOTO-LITHOBRAPHER. WASHINGTON. DV 0.

. z sheets-sheen.

W. C. MARGEDANT. SCROLL SAWING-MACHINE.

No. 170,578. Patented Nov. 30, 1875.

Z? n I H r WITNEf- E N.PETERS. PHOTO-LITHOGRAPMER, WASHINGTON. D C.

UNIT D STATES PATENT OFFIon.

WILLIAM C. MARGEDANT, OF HAMILTON, OHIO, ASSIGNOR TO BENTEL, MARGEDANT &00., OF SAME PLACE.

IMPROVEMENT IN SCROLL-ISAWING MACHINES.

Specification forming partof Letters Patent No. 170,578, dated November30, 1875 application filed July 28, 1875.

To all whom it may concern:

Be it known that I, WILLIAM C. MARGE: DANT, of Hamilton, in the countyof Butler and State of Ohio, have invented a new and useful Improvementin Scroll Sawing Machines; and I do hereby declare that the following isa full, clear, and exact description of the same, reference being had tothe accompanying drawings forming part of this specification, in which-Figure 1 is a front elevation of the jigsaw stand and the strainingapparatus with double springs. Fig. 2, asectional view through the line11 c. Fig. 3 shows the straining device consisting only of one springattached to a stanchion illustrating the different positions of the endsof the springs at the extremities of the movement of the saw-blade. Fig.4 is an elevation of the straining device, the fulcrum of the radiimoving on adjustable centers Fig. 5, a top view of Fig. 4; Fig. 6, anelevation of the cross-head; Fig. 7, a top view of the cross-head. Figs.8 and 9 are modifications of the spring; Fig. 10, a modification of thespring as adapted to be used with two acting levers.

My invention relates to that class of scrollsaws wherein a serratedlinear blade is given 'a vertically-reciprocating motion by means of acrank, pitman, and cross-head, and where the blade is held ata uniformtension or strain at all attitudes of the saw-blade.

My improvement refers particularly to the apparatus or device whichimparts to the'serrated blade a certain amount of strain necessary tosupport the blade in its rapid reciprocating motion.

Experience has established the fact that most of the devices now in usefor straining the blade are lacking those qualities which are necessaryto obtain the required result, viz., a uniform strain at any point ofthe motion, a quick and sensitive action, and the adjustability andsimplicity of wearing parts.

In the drawings, A is the main stand or table, cast in one piece,provided with the usual driving pulley, crank-wheel, pitman, crossheadM, and saw-holder. B is the stanchion or hanging standard, suitablyattached to the ceiling, and supporting the adjustable plate 0, whichcarries the adjustable springs D and D. The latter are held by thestraining-loops E E. (Shown in Figs. 2, 4, and 5.) The straining-loops EE pass through the spring-saddles F F. The spring-saddles are providedwith toothed collars G G, and pass through the adjustable plate 0, andare fastened by means of a screw-nut. The toothed collars G G are incontact with the ratchet-pawls H H. The ends of the springs D and D holdand press the radii levers I I, which are connected with the saw-bladeby leather strips or Wire rope. The adjustable springs D D are formed ofa bar of steel, which tapers oft toward the ends.

It is not essential that they should be tapered at all, or taperedtoward one or both ends. In some cases better results are obtained bymaking one end of the spring, which acts as the fulcrum of the radii orlever I,

heavier than the other end. The principle feature is the bending of thebar in a circular, oval, or other suitable form or shape, so that theends of the bar meet, as shown in Fig. 8; or that they pass in closeproximity, as shown in Fig. 9.

If only one lever is acting on both ends of one spring, the points ofcontact or pressure should not meet in the same line, as the pressure onone side of the lever would be counterbalanced by the pressure on theopposite side.

If two levers are applied to one spring, as shown in Fig. 10, the endsof the spring may meet in one common line. I prefer, now, theapplication of one lever for obtaining a reciprocating motion, becausethe number of parts and friction is reduced.

Between the bearing ends of the bent spring should be a certain distanceestablished to obtain leverage or mechanical advantages. The dimensionof the distance must be made in conformity with the amount of pressurerequired, strength and size of the spring, length of the lever, and thelength and acuteness of its action wanted.

Most of the springs which have been so far used for reciprocatingmachines, are irregular and multiplying in force. By the use of cone andeccentric pulleys, and other devices, this defect of springs has beenpartly remedied, but another defect estabIished-that of complicationof'pa-rts and connection, and consequentlj a loss of directmotion,.increase in weight, and friction.

. The construction of my improved spring, the attachment and operationof the lever, as well as the ad justability of the same, gives an equalstrain at the whole lengthiof motion,

.and consists of very few parts.

Fig. 3 shows a single spring in rest, and the position of the radiilever and spring when in action.

It will be noticed that the spring opens when the lever is depressed;but the distance between the ends of the spring, and consequently theleverage, and the leverage action between the same, are also diminished.By depressing the lever more, thepoints of pressure meet in one commonline. i

I prefer to arrange the spring and lever in such a manner as shown inFigs. 1, 2, and 3, if only light and quick sawing is required. For heavywork I believe the arrangement shown in Figs. 4 and 5 gives a betterresult. The difference in the latter device from the former consists inthe use of an adjustable fulcrum on which the lever swings.

It will be observed that in Figs. 1 and 3 the lower end of the spring Dis the fulcrum of the lever I; butit is not a fixed or stationaryfulcrum. Its action is similar to the upper part of the spring.

Figs. 4 and 5 show the lovers 1 I held by two pointed set screws, whichestablish-the fulcrum of the lever movement.

Thasprings may be adjusted to press more on the upper or lower side ofthe levers, as

the nature of the work may require.

The plate 0 can be provided with slots K, so as toadjust the springs,including centerscrews.

. The strain or pressure of the saw may be increased or reduced by thehand-wheel L.

Fig. 3 shows the arrangement on a large scale. The spring D rests onthespring-sad dle F on two higher points, f f, which said points orprojections cause the two ends of the spring D to be pressed togetherand stiffened when the straining-loop E is tightened, so that the saidspring may be adjusted as to its tension. By loosening a fastening onthe strain-loops E E, the two ends of the spring will impart lesspressure to the lever I.

the cross-head M. As that part of the machine should combine greatstrength andlight ness, I prefer to make it of two steel plates,

M M. A piece of suitable plate-steel is cut cylinder. The wooden pitmanis held to the journal-pin by means of washers O, which are held bysmall screws inserted partly in the hollow pitman-pin. As the screws X,which i hold the washers O and pitman P, do. not meet, an empty space isformed inthe pitman pin, which I fill with plumbago, or other suit ablelubricator. By boring several small holes, a, from the outside of thepitman-pin to the lubricating-chamber, the contentswill be thrown by thereciprocating force to the hearing parts of the pitman and pin.

By cutting-superfluous metal away, a webslide is produced with a hollowpin which is very light and strong, and which carries in itself alubricator which lubricates automati: cally the working parts when thesaw is, in

motion and lubrication is needed. The crankpin, connecting the pitmanwith the crankwheel, is also hollow, and provided with channels forlubrication.

The application of spring or springs, as specified, as well as that of alubricating-pin on other machines, I shall preserve.

Having thus described my invention, what I claim as new is-- 1.' In ascroll-saw, a straining or spring dey I vice consisting of a barof steelor other SlllU-fi able material, bent in such a form that both ends ofthe spring are in close proximity, in combination with a lever ofsuitable forminserted between the ends of the spring, as do,

scribed, so that the action of the spring is transmitted to the lever,and transformed thereby into a reciprocating motion, substan tially asdescribed.

2. In a scroll-saw, a spring formed of a bar of steel or suitablematerial, bent as described, so that the ends of the bar come inGIOSBiPI'OX- imity, in combination with a lever which swivels on anindependent fulcrum, while one end of the spring is active in front, andthe other end of the spring is active on theopposite side of the fulcrumof the lever, substan- 1 tially as described. r r

3. The slides formed of plates M M, in combination with the hollowpitman-pin, having holes a, the washers O, and screws X, as arranged,and for the purpose specified.

WM. 0. MARGEDANT.

Witnesses: 1

P. H. GERHARD, JOHN SEEMAN.

